Introduction
When beef tenderloin is on sale, I like to think of it as “several good dinners,” not just a single fancy meal. Cut what you need for tonight, and you’ve got the rest ready for pasta, salads, or another steak night later in the week.
The sides stay simple: roasted sweet potato in big chunks (soft inside, a bit of color outside), lightly sautéed shallots, and mushrooms that get the treatment they deserve in a hot pan. Add béarnaise and something green and you’re set.
Quick overview: Slice off enough steak for tonight and keep the sides simple. Cut sweet potatoes into big chunks (not too small) and roast for about an hour. Slice shallots into rings and sauté lightly. Cook mixed mushrooms (oyster, porcini, portobello) in a dry pan first to drive off moisture, then finish with butter/oil for deep browning. Serve with béarnaise and a bit of salad.
Step-by-step
Ingredients (serves 3–4)
- 700–900 g beef tenderloin (1.5–2 lb), cut into 3–4 pieces
- 2 large sweet potatoes (about 900 g / 2 lb), cut into 2.5–3 cm chunks (1–1¼ in)
- 3 shallots, sliced into rings
- 400 g mixed mushrooms (14 oz), cut into large pieces
- 30 g butter (2 tbsp) (for mushrooms and steak)
- 20 ml oil (1½ tbsp) (for mushrooms and steak)
- 16–18 g salt (about 3 tsp) (total, to taste)
- Black pepper
- 2–3 g thyme (optional)
- Béarnaise sauce, to serve
- A little salad/arugula, to serve
Method
- Preheat the oven to 200 °C / 390 °F.
- Sweet potatoes: Toss the chunks with a little oil, salt, and pepper. Spread on a sheet pan and roast for 45–60 minutes, turning once, until tender and nicely colored.
- Mushrooms: Heat a large pan over medium-high. Cook the mushrooms in a dry pan first until they release water and most of it evaporates. Add butter and a bit of oil, season with salt/pepper (and thyme if using), and brown well. Set aside.
- Shallots: In the same pan, add a touch of butter and sauté the rings over medium until soft and lightly golden. Set aside.
- Steak: Pat dry, season generously with salt and pepper. Sear in a very hot pan with a little oil until you get a good crust, about 2–3 minutes per side (depending on thickness). Add a knob of butter near the end and baste. Rest 5–10 minutes.
- Serve: Plate the sweet potatoes, top with steak, mushrooms, and shallots. Add béarnaise and a little salad on the side.
Tips
- The mushroom trick: dry pan first means better flavor and better browning once the fat goes in.
- Leftover steak: slice thinly cold the next day and use in a salad with any leftover mushrooms and a simple vinaigrette.
